In fuel burning apparatuses and internal combustion engines, combustion of a fuel generally occurs with an oxidizer, such as air, in a combustion chamber. Expansion of the high temperature/pressure gases produced by the combustion can directly apply force to a movable component of the engine, such as pistons or turbine blades and generate useful mechanical energy.
A large number of different designs for combustion engines have been developed and built, with a variety of different strengths and weaknesses. Most combustion engines are designed to burn a particular fuel in a particular state or phase of matter. For example, internal combustion engines may be designed to burn gasoline or diesel fuel. Furnaces or boilers often burn natural gas, oil, or coal. Some engines use the fuel as a liquid, some use the fuel as a gas, or vapor.
Some fuel burning apparatuses have been developed which treat fuel before combustion. Such treatment devices are sometimes called fuel pretreaters and may treat the fuel in a variety of ways, such as vaporizing a liquid fuel, heating the fuel, mixing the fuel, etc. Pretreating fuel prior to combustion can serve to increase efficiency of converting energy in the fuel into work which can be performed by the fuel burning apparatus. Improving fuel efficiency even marginally can result in substantial fuel savings over a period of time. Improved fuel efficiency can also provide environmental benefits. Using less fuel can result in fewer harmful emissions to the atmosphere. Exhaust from fuel burning engines can be cleaned to reduce harmful emissions as well.
Despite the wide variety of fuel burning apparatuses, engines, and the like, prior devices still often are unacceptably inefficient or produce an unacceptable amount of harmful emissions. Combustion devices have been developed which are able to reduce harmful emissions and increase fuel efficiency.